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Hafnium Facts

Chemical & Physical Properties

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Elemental hafnium metal, with a penny to indicate the scale.

Elemental hafnium metal, with a penny to indicate the scale.

U.S. Geological Survey
Periodic Table of the Elements

Hafnium

Symbol: Hf

Atomic Number: 72

Atomic Weight: 178.49

Element Classification: Transition Metal

Electron Configuration: [Xe] 4f14 5d2 6s2

Discovery: Dirk Coster and Georg von Hevesy 1923 (Denmark)

Name Origin: Hafnia, the Latin name of Copenhagen.

Density (g/cc): 13.31

Melting Point (K): 2503

Boiling Point (K): 5470

Appearance: silvery, ductile metal

Atomic Radius (pm): 167

Atomic Volume (cc/mol): 13.6

Covalent Radius (pm): 144

Ionic Radius: 78 (+4e)

Specific Heat (@20°C J/g mol): 0.146

Fusion Heat (kJ/mol): (25.1)

Evaporation Heat (kJ/mol): 575

Pauling Negativity Number: 1.3

First Ionizing Energy (kJ/mol): 575.2

Oxidation States: 4

Lattice Structure: hexagonal

Lattice Constant (Å): 3.200

Lattice C/A Ratio: 1.582

References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)

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